332 MORPHOLOGY AND EVOLUTION
Man, One line led away to the Orang, and another led up to the African Simiidse and Man. It is possible that the forms which gave rise to the African Simiidse included Dryopithecus and Sivapithecus. The observations of Keith (102) and others lead to the view that the human stock separated from the Anthropoid stock in the Miocene Period; and Elliot Smith has pointed out that Man separated from the Apes as the result of cerebral changes, which enabled him to use his hands and voice and to profit by experience. The early members of the human stem were unlike modern Man, for they probably retained simian characters right through the Miocene and part of the Pliocene Period. And it is not till we arrive at the early part of the Pleistocene Period that true human remains appear. Should the fragments of the so-called Java Man (Pithecanthropus credits) turn out to be human remains of a low type we can assign the later part of the Pliocene Period as the date of the appearance of Man. Keith and others believe that Man assumed his characteristic human features in the Pliocene Period.
After their differentiation from common ancestral forms in the Siwalik Eegion the Apes and the ancestors of Man became dispersed. The Orang passed to Borneo and Sumatra, and the Chimpanzee and Gorilla settled down in Africa. They all retained certain constitutional resemblances, for the blood of Man and the Apes exhibits similar reactions. Changes were induced in their somatic features as the result of variations in the functions of their ductless glands ; and it is probable that climatic and dietetic factors played important parts in inciting differerfcces in function. They also exhibit differences in